Sound deadener



L 1 22,4 March 29, l1927, w' A. SCOTT l ,6 69

SOUND DEADENER Filed' May 24.V 1926 2W vf/va WHA rm 500 rr r M5 /i fr0/M5 yi Patented Mar. 29, 1927.

UNITED` STA-TES Parri-:Nr OFFICE.

WALTER A. SCOTT, OF MINNEAPOLIS, MINNESOTA.

soUND DEDENEB.

Application filed May 24,

sound, such as in walls, heavy machinery, car

wheels, typewriters, sound screens, etc.

A further, object is to provide a sound deadening structure including a filling or wall of small nonresonant particles, adapted to disintegrate sound vibrations and contacting each other in the least possible manner, whereby' the transmission of sound will be minimized.

In most forms of sound deadening material and insulation the wall or filling, although capable ot disintegrating sound vibrations to a considerable extent, will transmit a considerable amount of sound due to the fact that the filling elements contact each other extensively or that the material is pressed or rolled into a relatively compact sheet. I provide a sound deadening wall formed from a plurality of loosely packed, relatively nonresonant spherical particles which cause the sound vibrations to be broken and which contact each other only at one point, that is,their point ot tangency. Where irregular or cubical particles are used as a iller the several particles touch each other along considerable areas of their surfaces and thus transmit a considerable amount ot sound. Y

Ain additional object of this invention is to y provide a sound deadening'st-ructure especially adapted for revoluble members, such as gears and wheels.

These and other objects of the invention will be apparent from the following description made in connection with the accompanying drawings, wherein like characters refer to similar parts throughout the several views, and'in which- Y Fig. 1 is a cross section of a sound deadc'ning wall made in accordance with my inven tion;

Fig. 2, is a side elevation ot a car wheel having my invention embodied therein,

Fig. 3 is an end view taken on Fig. 2 with some portions broken away and others shown in section, and

Fig. 4 is a detail view on a greatly 'cnlarged scale showingone of the minute elements. f

-In Fig. 1 of the drawings, a pair of vertical partitions 5 and 6 are illustrated spaced 1926. Serial No. 111,470.

some distanceapart. The right hand partition 6 is shown as having its lower en d turned up to forma bottom 6a,-between the edge of which and the lower end of partition 5 I provide apaclring strip of nonresonant material. lThe space between partitions 5 and 6A is filled with a .multiplicity ot minute spherical particles preferably constructed of vnonresonant material. vWhile a great variety of material may be used, lead shot, such as employed in shot gun shells or small carbon spheres have been found highly eiiicient.

fallsl 5 and 6 may be secured together in spaced relation in any suitable manner, and are here shown as secured by a transversely disposed nutted bolt 8. y

Figs. 2 and 3 illustrate a,noiseless type of car wheel constructed in accordance with my invention. The wheel proper 9 is constructed in .the usual manner having a relatively heavy hub 10 and the flanged treadportion 11. In many types of car wheels, suoli as are employed on railway and street cars depressed portions or annular recesses are formed in the wheel about the hub and extending adjacent thc tread portion. It the wheel is not provided with annular recesses, as described the same may be easily machined therein on both sides ot the wheel and pret erably narrow annular -shoulders 12 are left at the edges of the recess, the purpose ot which will be readily seen. These recesses are iilled with a relatively thin layer of small nonresonant spherical particles X on 'the outer sides of which annular plates 13 are clamped. Annular packing strips are disposed between the shoulders 12 and the adjacent edges of the plates to minimize the transmission of sound. The plates may be clamped to wheel 9 in any suitable manner,

and are .here shown as secured by means of a pluralityV of transversely disposed nutted bolts 15, passing through plates 13 and through the wheel proper.

It is, vof course, a well known fact that sound vibrations will be greatly disintegrated and prevented in passing, or attempting to pass through a wall formed of nonresonant particles. If these particles are uniform in size and shape, the eliiciency of the device will be greater, since the spaces between the particles are apt to be more regular and smaller.

However, where the particles contact each other considerably, the wall so formed, even though constructed of comparatively nonable amount of sound vibrations.

.transmitting-sound, since each particle can touch an adjacent particle at only one point,

and since moreover, the particles will be packed in very closel arrangement thereby being operative to more thoroughly disin-.`

tegrate the sound \-'ibrations.` No'binding material is used-between the particles.

Myl structure, therefore both minimizes the transmission of sound through the wall and gives a maximum disintegration of thc vibrations in traveling therethrough.

While the spherical particles may be formed of various other nonresonant material, line gun shot has been found to have the highest degree of 'efficiency' Lead' of course is a comparatively nonresonant material, may be cheaply obtained and easily melted 'to form the spherical particles.

Moreover, in heavy machinery and Wheels,

where often it is desired not to .lessen the weight of the parts, a thin layer of this material maybe used to accomplish. the purposes desired.

It will, of course, 4be understood lthat various changes may be made in the form, -details, proportions and arrangement of parts, and that'my sound deadening .structure -is capable of application to any use Where it is desired to eliminatevor minimize sound vibrations, without departing from the scope` of this invention.

What is claimed is: l. A sound absorbing wall comprising a multiplicity of substantially spherical ununited particles of non-resonant mat-trial and means to retain said particles in contacting relation. v

2. A sound absorbing construction including a multiplicityof symmetrical members of non-,resonant materialarranged over a substantial portion ofthe surface of sound.

emitting body. l

3. A sound absorbing construction including a multiplicity of ,ununited spherical members of non-resonant material arranged WALTER A. sCoTT.

over a substantial portion of the surface of a 

